Short for single instruction, multiple data. A type of parallel computing architecture that is classified under Flynn's taxonomy. A single computer instruction perform the same identical action (retrieve, calculate, or store) simultaneously on two or more pieces of data (Charles Belov, 1997). * Typically this consists of many simple processors, each with a local memory in which it keeps the data which it will work on. Each processor simultaneously performs the same instruction on its local data progressing through the instructions in lock-step, with the instructions issued by the controller processor. The processors can communicate with each other in order to perform shifts and other array operations. [* Source: EPCC]